<html>
<body onclick="">
<div style="float:left;width:500px; border: 1px solid black;">
  <div>
    <div style="float:right;">
      <div style="padding-top: 50px; background-color: green;">
        <img id="a" src="">
      </div>

    </div>
    <div style="float:right;width:150px;height:150px;clear:right; background-color:blue;"></div>
    <h2>This text should not overlap with the green box</h2>
  </div>
</div>
<script>
document.body.offsetTop;
document.getElementById('a').style.width='300px';
</script>
</body>
</html>
